<!DOCTYPE html>
<html lang="en">
<head>
	<meta charset="UTF-8">
	<title>Document</title>
	<style type="text/css">
		div{
			width: 200px;
			height: 200px;
			background: red url() 0 0 no-repeat;
			overflow: hidden;
			position: relative;
		}
		div:after{
			/*display: block;*/
			content: '4545';
			color: red;
			position: absolute;
			top:0px;
			left: 0px;
			/*width: 200px;
			height: 200px;
			background: blue url() 0 0 no-repeat;*/
		}
	</style>
</head>
<body>
	<div>中中在枯无可奈何花落去中中在枯无可奈何花落去中中在枯无可奈何花落去</div>
	<section name="yunsuan">
		<option value="+">+</option>
		<option value="-">-</option>
		<option value="*">*</option>
		<option value="/">/</option>
	</section>
</body>
</html>